Allenes. Part XIX. Synthesis of (±)-hypoglycin A and configuration of the natural isomer
作者:D. K. Black、S. R. Landor
DOI:10.1039/j39680000288
日期:——
The synthesis of hypoglycin A by way of the allenic intermediate, diethyl 1-formylaminopenta-3,4-diene-1,1-dicarboxylate, by Simmons–Smith methylation, is described. Model experiments with ethyl buta-2,3-dienoate and diethyl allyl(formylamino)malonate gave ethyl methylenecyclopropanecarboxylate and, after hydrolysis and decarboxylation, 2-amino-3-cyclopropylpropionic acid. Degradation of hypoglycin
Synthesis of 3-amino-2,3-dideoxytetrose derivatives
作者:S. David、A. Veyrières
DOI:10.1016/s0008-6215(00)80826-5
日期:1970.5
route, methyl 2-amino-4,4-dimethoxybutyrate (5) was prepared from dl -aspatic acid. Reduction of 5 with lithium aluminium hydride yielded 3-amino-4-hydroxybutyraldehyde dimethylacetal (6 from which the N-acetyl derivative 7 and the diethyl dithioacetal 9 could be prepared. Acid hydrolysis of the (S-isome 7′ of compound 7, prepared from l -aspartic acid, yielded the crystalline 3-acetamido-2,3-dideoxy-
A conformationally restricted cyclic pentapeptide, containing an unsaturated 9-membered lactam as a semi-rigid scaffold, was prepared in a very convergent manner, through tandem Ugi reaction/ring closing metathesis.
Enantioenriched 2-azabicyclo[3.1.0]hexanes are accessed from readily available allyl substituted α-isocyanoesters by intramolecular (1 + 2) cycloaddition with the olefinic moiety and isocyano carbon as the respective C2 and C1 units. Cyclopropanation is initiated by 1,1-hydrocupration of isocyanide followed by formimidoylcopper to copper α-aminocarbenoid equilibration and subsequent (1 + 2) cycloaddition